The present invention relates to a direct driving type optical fiber switch, especially to a direct driving type optical fiber switch using V-groove to enhance alignment accuracy.
There has always been a demand for increased capacity of transmission for information. The lightwave communication system using optical fiber provides an ideal solution for mass data transmission. More particularly, the optical fiber has advantages of low loss transmission over long distance, high security, immunity to EMI, and lightweight. Therefore, the conventionally fancy technology such as fiber to the curb (FTTC) and fiber to the building (FTTB), even fiber to the home (FTTH) and fiber to the desktop (FTTD) becomes mature and popular. The optical fiber switch is an important component for building optical network and therefore is under extensive research and improvement.
FIGS. 1A and 1B show a prior art optical switch disclosed in U.S. Pat. No. 5,434,936. The prior art optical switch comprises a movable optical fiber 101 with an end fixed to a tip of a cylindrical tube 103 and with another end extruding into a cylindrical sleeve 106. Two magnetic bodies 110a and 110b in a pipe shape arranged atop the input optical fiber 101. Solenoid coils 105a and 105b are provided so as to surround the two magnetic bodies 110a and 110b. A pair of permanent magnets 107a and 107b is located paralleled to the magnetic body 110a and at equivalent intervals, and having the magnetic poles in the opposite direction. A pair of permanent magnets 107c and 107d is located paralleled to the magnetic body 110b and at equivalent intervals, and having the magnetic poles in the opposite direction. There are four fixed optical fibers 102a, 102b, 102c and 102d, one of whose tips is opposite to a tip of the movable optical fiber 101, and which are fixed in a corner of a square hole within a columnar member 104 fixed within the cylindrical sleeve 106. arranged atop the input optical fiber 101. The magnetic fields of the solenoid coils 105a and 105b are attracted or repelled by those of the permanent magnets 107a, 107b, 107c and 107d, thus moving the movable optical fiber 101 to a selected corner of the square hole within a columnar member 104.
However, in above-mentioned optical switch, the switch of the movable optical fiber is achieved by the composite action of the solenoid coils and the permanent magnets. It is hard for the tip of the movable optical fiber to locate at a specific and accurate location. Therefore, considerable manual adjustment is required. The yield is reduced and the cost is increased.
Alternatively, the movable input optical fiber can be moved by a step motor. However, the positioning error for fiber alignment is required to be below xc2x10.5 xcexcm. This imposes strict restriction for the accuracy of the step motor. Moreover, the maintenance and purchase costs are increased.
It is the object of the present invention to provide a direct driving type optical fiber switch with simple structure and reduced cost.
In one aspect of the present invention, the optical fiber switch uses V-groove to enhance alignment accuracy and uses at least one positioning block to clamp the movable input optical fiber into a selected V-groove.
In another aspect of the present invention, the optical fiber switch uses V-groove and positioning block to reduce alignment error and enhance yield.
In still another aspect of the present invention, the optical fiber switch uses V-groove and positioning block to reduce the accuracy requirement for each device, thus decreasing cost.